// Set that represents hash table H
// (i.e., hash table that records encountered states)
// VOD graph is updated when the state has not yet been seen
- private HashSet<Integer> visitedStateSet;
// Current state
private int stateId;
+ // Previous state
+ private int prevStateId;
// Previous choice number
private int prevChoiceValue;
+ // Counter for a visited state
+ private HashMap<Integer, Integer> visitedStateCounter;
+ // HashSet that stores references to unused CGs
+ private HashSet<IntChoiceFromSet> unusedCG;
public StateReducer(Config config, JPF jpf) {
debugMode = config.getBoolean("debug_state_transition", false);
transition = null;
isBooleanCGFlipped = false;
vodGraphMap = new HashMap<>();
- visitedStateSet = new HashSet<>();
stateId = -1;
+ prevStateId = -1;
prevChoiceValue = -1;
cgMap = new HashMap<>();
readWriteFieldsMap = new HashMap<>();
backtrackMap = new HashMap<>();
backtrackSet = new HashSet<>();
conflictPairMap = new HashMap<>();
+ unusedCG = new HashSet<>();
+ visitedStateCounter = new HashMap<>();
initializeStateReduction();
}
isInitialized = true;
}
// Record the subsequent Integer CGs only until we hit the upper bound
- if (!isResetAfterAnalysis && choiceCounter <= choiceUpperBound && !cgMap.containsValue(choiceCounter)) {
- // Update the choices of the first CG and add '-1'
- if (choices == null) {
- // Initialize backtrack set that stores all the explored backtrack lists
- maxUpperBound = cgChoices.length;
- // All the choices are always the same so we only need to update it once
- choices = new Integer[cgChoices.length + 1];
- System.arraycopy(cgChoices, 0, choices, 0, cgChoices.length);
- choices[choices.length - 1] = -1;
- String firstChoiceListString = buildStringFromChoiceList(choices);
- backtrackSet.add(firstChoiceListString);
+ if (!isResetAfterAnalysis) {
+ if (choiceCounter <= choiceUpperBound && !cgMap.containsValue(choiceCounter)) {
+ // Update the choices of the first CG and add '-1'
+ if (choices == null) {
+ // Initialize backtrack set that stores all the explored backtrack lists
+ maxUpperBound = cgChoices.length;
+ // All the choices are always the same so we only need to update it once
+ choices = new Integer[cgChoices.length + 1];
+ System.arraycopy(cgChoices, 0, choices, 0, cgChoices.length);
+ choices[choices.length - 1] = -1;
+ String firstChoiceListString = buildStringFromChoiceList(choices);
+ backtrackSet.add(firstChoiceListString);
+ }
+ icsCG.setNewValues(choices);
+ icsCG.reset();
+ // Advance the current Integer CG
+ // This way we explore all the event numbers in the first pass
+ icsCG.advance(choices[choiceCounter]);
+ cgMap.put(icsCG, choices[choiceCounter]);
+ } else {
+ // We repeat the same trace if a state match is not found yet
+ icsCG.setNewValues(choices);
+ icsCG.reset();
+ // Use a modulo since choiceCounter is going to keep increasing
+ int choiceIndex = choiceCounter % (choices.length - 1);
+ icsCG.advance(choices[choiceIndex]);
+ unusedCG.add(icsCG);
}
- icsCG.setNewValues(choices);
- icsCG.reset();
- // Advance the current Integer CG
- // This way we explore all the event numbers in the first pass
- icsCG.advance(choices[choiceCounter]);
- cgMap.put(icsCG, choices[choiceCounter]);
choiceCounter++;
} else {
- // Set done the subsequent CGs
- // We only need n CGs (n is event numbers)
+ // Set new CGs to done so that the search algorithm explores the existing CGs
icsCG.setDone();
}
}
Set<Integer> eventSet = backtrackMap.keySet();
// Return if there is no conflict at all (highly unlikely)
if (eventSet.isEmpty()) {
+ // Set every CG to done!
+ for (IntChoiceFromSet cg : cgMap.keySet()) {
+ cg.setDone();
+ }
return;
}
// Reset every CG with the first backtrack lists
cg.setDone();
}
}
+ // Set done every CG in the unused CG set
+ for (IntChoiceFromSet cg : unusedCG) {
+ cg.setDone();
+ }
+ unusedCG.clear();
+ }
+
+ private void incrementVisitedStateCounter(int stId) {
+ // Increment counter for this state ID
+ if (visitedStateCounter.containsKey(stId)) {
+ int stateCount = visitedStateCounter.get(stId);
+ visitedStateCounter.put(stId, stateCount + 1);
+ } else {
+ // If we have seen it then the frequency is 2
+ visitedStateCounter.put(stId, 2);
+ }
+ }
+
+ private boolean isVisitedMultipleTimes(int stId) {
+ // Return true if the state has been visited more than once
+ if (visitedStateCounter.containsKey(stId) &&
+ visitedStateCounter.get(stId) > 1) {
+ return true;
+ }
+ return false;
}
@Override
readWriteFieldsMap.clear();
choiceCounter = 0;
}
- // Traverse the sub-graphs
- if (isResetAfterAnalysis) {
- // Advance choice counter for sub-graphs
- choiceCounter++;
- // Do this for every CG after finishing each backtrack list
- if (icsCG.getNextChoice() == -1 || visitedStateSet.contains(stateId)) {
- if (cgMap.containsKey(icsCG)) {
+ if (!vm.isNewState()) {
+ incrementVisitedStateCounter(stateId);
+ }
+ // Check if we have seen this state and it's not looping back to itself
+ if (prevStateId != -1 && stateId != prevStateId && isVisitedMultipleTimes(stateId)) {
+ // Traverse the sub-graphs
+ if (isResetAfterAnalysis) {
+ // Advance choice counter for sub-graphs
+ choiceCounter++;
+ // Do this for every CG after finishing each backtrack list
+ // We try to update the CG with a backtrack list if the state has been visited multiple times
+ if ((icsCG.getNextChoice() == -1 || choiceCounter > 1) && cgMap.containsKey(icsCG)) {
int event = cgMap.get(icsCG);
LinkedList<Integer[]> choiceLists = backtrackMap.get(event);
if (choiceLists != null && choiceLists.peekFirst() != null) {
icsCG.setDone();
}
}
+ } else {
+ // Update and reset the CG if needed (do this for the first time after the analysis)
+ // Start backtracking if this is a visited state and it is not a repeating state
+ resetAllCGs();
+ isResetAfterAnalysis = true;
}
}
- // Update and reset the CG if needed (do this for the first time after the analysis)
- if (!isResetAfterAnalysis && icsCG.getNextChoice() == -1) {
- resetAllCGs();
- isResetAfterAnalysis = true;
- }
}
}
}
choiceSet.add(currChoice);
}
+ private void updateStateId(Search search) {
+ // Saving the previous state
+ prevStateId = stateId;
+ // Line 19 in the paper page 11 (see the heading note above)
+ stateId = search.getStateId();
+ }
+
@Override
public void stateAdvanced(Search search) {
if (debugMode) {
if (stateReductionMode) {
// Update vodGraph
int currChoice = choiceCounter - 1;
- if (currChoice < 0 || currChoice > choices.length - 1 || choices[currChoice] == -1 || prevChoiceValue == choices[currChoice]) {
+ // Adjust currChoice with modulo
+ currChoice = currChoice >= 0 ? currChoice % (choices.length -1) : currChoice;
+ if (currChoice < 0 || choices[currChoice] == -1 ||
+ prevChoiceValue == choices[currChoice]) {
+// || currChoice > choices.length - 1 || choices[currChoice] == -1 ||
+// prevChoiceValue == choices[currChoice]) {
+// // When current choice is 0, previous choice could be -1
+// updateVODGraph(prevChoiceValue, choices[currChoice]);
+// // Current choice becomes previous choice in the next iteration
+// prevChoiceValue = choices[currChoice];
+ // Update the state ID variables
+ updateStateId(search);
// Handle all corner cases (e.g., out of bound values)
return;
}
updateVODGraph(prevChoiceValue, choices[currChoice]);
// Current choice becomes previous choice in the next iteration
prevChoiceValue = choices[currChoice];
- // Line 19 in the paper page 11 (see the heading note above)
- stateId = search.getStateId();
- // Add state ID into the visited state set
- visitedStateSet.add(stateId);
+ // Update the state ID variables
+ updateStateId(search);
}
}
transition = search.getTransition();
detail = null;
+ // Update the state variables
+ // Saving the previous state
+ prevStateId = stateId;
+ // Line 19 in the paper page 11 (see the heading note above)
+ stateId = search.getStateId();
+
out.println("\n==> DEBUG: The state is backtracked to state with id: " + id + " -- Transition: " + transition +
" and depth: " + depth + "\n");
}
public void instructionExecuted(VM vm, ThreadInfo ti, Instruction nextInsn, Instruction executedInsn) {
if (stateReductionMode) {
if (isInitialized) {
- if (choiceCounter > choices.length - 1) {
+ if (choiceCounter <= 0 || choiceCounter > choices.length - 1) {
// We do not compute the conflicts for the choice '-1'
return;
}
// If it has been serviced before, we just skip this
if (recordConflictPair(currentChoice, eventNumber)) {
// Lines 4-8 of the algorithm in the paper page 11 (see the heading note above)
- if (!visitedStateSet.contains(stateId)||
- (visitedStateSet.contains(stateId) && isReachableInVODGraph(choices[currentChoice], choices[currentChoice-1]))) {
+ if (vm.isNewState() ||
+ (!vm.isNewState() && isReachableInVODGraph(choices[currentChoice], choices[currentChoice-1]))) {
createBacktrackChoiceList(currentChoice, eventNumber);
// Break if a conflict is found!
break;
projects / jpf-core.git / commitdiff